It is known to use plastic cards having a magnetic code to activate door locks in buildings. For example, many businesses issue employees with security swipe cards, each card having a magnetic strip or some alternative, to enable employees to open locked doors and enter areas from which it is desired to exclude non-authorised personnel. Employees may also be issued with identity cards, or alternatively a single card to achieve both security and identity functions. It is also known to provide such employees with a holder for such cards which can be attached to clothing of the employees by way of a retractable line or the like. A disadvantage with many known holders is that they are only able to receive and hold one card. It is accordingly an object of at least one form of the present invention to go at least some way towards addressing this disadvantage, or to at least provide the public with a useful choice.